Explain why a hash function is not appropriate for encrypting data (even if you use a key with it).

Say you are given a hash function that produces an 80-bit digest, along with a message digest d. Using random guessing, how many guesses would you expect it to take to find a preimage?

2^80 (CORRECT?) Say you are given an 80-bit hash function as in the previous question. Using random guessing, roughly how many guesses should it take to find two messages with the same digest?

h(m1)=h(m2)

2^80 (CORRECT?) or 2^40